Cyrus Stephen Eaton, Sr. (December 27, 1883 – May 9, 1979) was a Canadian-American investment banker, businessman and philanthropist, with a career that spanned seventy years.[1][2]

For decades Eaton was one of the most powerful financiers in the American Midwest, and he was a colourful and often-controversial figure.[3][4] He was chiefly known for his longevity in business, for his opposition to the dominance of eastern financiers in the America of his day, for his occasionally ruthless financial manipulations, for his passion for world peace and for his outspoken criticism of United States Cold War policy. He funded and helped organize the first Pugwash Conferences on World Peace, in 1955.[3] He wrote numerous articles and essays on political and economic subjects—Investment Banking, Competition or Decadence, Rationalism Versus Rockefeller, A Capitalist Looks at Labour, being some of the best known.[5]

After graduating from McMaster he moved to Cleveland and went to work for the East Ohio Gas Company. This was one of many businesses associated with John D. Rockefeller. After working with Ohio Gas and Rockefeller for two years, he established his own business in 1907, developing gas utilities which at the time were relatively underdeveloped and unconsolidated in Canada. He managed to secure natural-gas franchises in Manitoba, Canada representing a group of New York investors. The syndicate was not able to complete its financing and folded. However, the Manitoba government was sufficiently impressed to allow Eaton to retain the franchises. Eaton formed a new holding company, the Canada Gas & Electric Corp, later consolidated into the Continental Gas & Electric Corp. in 1913.

After spending several years traveling, Eaton settled in Cleveland in 1913 and became active in many businesses. Eaton joined the Otis & Co. banking firm in 1916. In 1926 he set up an investment vehicle organized as Continental Shares, Inc., a closed end trust. In 1927 he formed Republic Steel, the 3rd-largest U.S. steel company. His business had a complex structure which some felt to be too highly leveraged. His 1929 wealth was an estimated $100 million, most of which was lost in the Great Depression.

Eaton rebuilt his fortune in the 1940s and 1950s, becoming a director (1943), then board chairman (1954), of the Chesapeake and Ohio Railway; and also board chairman of the West Kentucky Coal Co. (1953).[4]

Besides financial support for the Pugwash Conferences, Eaton gave money to support education in Nova Scotia, particularly in Pugwash and to Acadia University. He supported the establishment of a game sanctuary in Nova Scotia on the Aspotogan Peninsula (his summer home was in Blandford, Nova Scotia where he had his ashes buried, His summer home was destroyed in a fire 2015; he donated the doors for the local church), and 12 acres (4.9 hectares) of land in Northfield, Ohio, for the Lee Eaton Elementary School, named in memory of his daughter. He was also a financial supporter of McMaster University, the YWCA, the Cleveland Museum of Natural History and Case Western Reserve University.